Arming cover for fuses



Feb. 26, 1952 J. RABINOW ARMING COVER FOR FUSES' 2 SHEETS-SHEET 1 Filed 001:. 25, 1946 JAcna FxAamclw Feb. 26, 1952 mow 2,586,861

ARMING COVER FOR FUSES Filed 006%. 25, 1946 '2 SHEETS-SHEET 2 JABUE RAEINDW Patented Feb. 26, 1952 ARMING COVER FOR FUSES Jacob 'Rabinow, Washington, D. 0., assignor to the United States of America as represented by the Secretary of -War Application October 25, 1946, Serial No. 705,787

(Granted under the act of March 3, 1883, as amended April 30, 1928; 3'70 0. G. 757) 6 Claims.

The invention described herein may be manufactured and used by or for the Government'for governmental purposes, without the payment to me of any royalty thereon.

The present invention relates to projectile and bomb 'fuzes and, more particularly, to delayed arming mechanisms therefor.

It is the practice to incorporate mechanisms in fuzes whereby arming of the fuzes may be delayed for a predetermined period of time or distance of air travel after the projectile is fired or dropped in order to avoid premature detonation. Among the mechanisms used are devices of the arming vane type by which a small, propeller-like vane, spinning in the air stream, disengages the safety devices of the fuze or otherwise arms the fuze. The amount of time or distance of flight required to arm the fuze generally is predetermined by the design of the arming device, although such time or distance obviously could be shortened by prespinning the vane a desired amount less than that required for arming. It was not found feasible to design arming mechanisms which could be varied over wide ranges of time or distance, primarily because of space limitations. Accordingly, as the need arose for fuzes of widely ranging arming time or distance characteristics, it became necessary to provide an undesirably large number of types of fuzes which gave rise to a difiicult problem of supply and complicated the use of the fuzes as well'as increasing the possibility of mistake.

Accordingly, it is an object of the present invention to provide a device for varying the arming distance of conventional fuzes over a wide range.

A furtherobject of the invention is to provide an arming delay device which can be attached to existing fuzes without modifying the same.

Another object is to provide such an auxilliary arming delay mechanism which will be detached from the fuze while the fuze is in flight to permit the normal arming and functioning of the fuze.

A further object of the invention is to provide such an arming delay mechanism which may be easily adjusted to provide a predetermined arming delay within a wide range.

The accomplishment of the foregoing and other objects will be apparent from the following description of a specific embodiment of the inven- Figure 3 is a cross-sectional view taken along the line 3-3 of Figure 4;

Figure 4 is a cross-sectional view the line 4-5 of Figure 3; and

Figure 5 is a cross-sectional view taken-along the line 5-5 of Figure 4.

Referring to the drawings wherein like reference numerals designate like parts throughout, reference numeral l designates the nose of a standard fuze having an air turbine 2 rotatably mounted thereon and provided with a guard ring 3 mounted on spaced supports 4. The rotation of air turbine 2 functions to .arm the fuze by means not shown in the drawing and not forming a part of the present invention.

The arming delay device embodying the present invention comprises a housing consisting of two cover halves 5 and 6 adapted to fit over the fuze nose I to shield the turbine 2 from air currents, thus effectively keeping the fuze from arming. If desired, a protuberance 36 may be provided on one of the cover halves to engage the blades of turbine 2 as an extra safety measure.

The cover halves 5 and 6 are secured adjacent the midpoint of their exterior surfaces to the ends of a straight spring leaf 1 which normally maintains the cover halves 5 and 6 in the opened position shown in Figure '2'. Curved projections 8 and 9 on cover half 5 and curved projections l0 and II on cover half 6 form bearing surfaces whereby the cover halves may be manually pivoted, as though hinged, into a closed position about the fuze nose I as shown in Figure 1. In the closed position the guard ring 3 is received within annular grooves 12 and I3 in cover halves 5 and 5, respectively, whereby the cover is effectively prevented from becoming disengaged from the fuze nose I except by being opened as shown in Figure 2. A struck-up flange I4 may be provided along the upper edge of cover half 5 to overlap the upper edge l5 of cover half 6 to more eifectively prevent air currents from reaching the turbine 2.

The cover halves 5 and 6 are maintained in a closed position about the fuze nose I and in engagement therewith by means of a projecting latch [B on the edge of cover half 5 which is adapted to be inserted through a notch I! in a 5 taken along dial [8 secured to one end of a shaft 20 which is rotatably mounted in a housing I9, which housing is secured to the meeting edge of cover half 6. It will be apparent that a turn of the dial l8 after the latch 16 is inserted through the notch I! will lock the cover halves 5 and 6 in closed position as shown in Figure 2.

"Theshait 15 :to which the died 18 lis'afilxed-is provided with a spur gear 2|, adapted to engage a pinion gear 22 on rotatable shaft 23. The end of shaft 20 opposite from the dial I8 is mounted in an elongated slot 24 in the housing H! which permits the shaft 20 to be moved sufilciently to engage and disengage the spur gear 2| from pinion gear 22. A torsional spring member 25 mounted on the housing [9 and bearing against the shaft 20 normally maintains the spur gear 2! and pinion gear 22 in mesh. However, the force of spring member 25 may be readily overcome by manual pressure on the end of shaft 20, thereby disengaging gears 2| and 22 to permit shaft 20 to turn freely thereby facilitating the setting of dial [8.

The rotatable shaft 23 is driven by an air vane 26 mounted on a rotatable shaft 35 throu h a gear train comprising worm 21 on shaft 35, worm gear 28 and worm 29 mounted on rotatable shaft 30, worm gear 31 and pinion gear 32 mounted on rotatable shaft 33, and spur gear 34 mounted on the said rotatable shaft 23.

It will thus be seen that when spur gear 2i and pinion gear 22 are engaged, rotation of the air vane 25 will relatively slowly rotate the dial I8 to a position where the notch H is aligned with the latch it, thus releasing the cover halves and 6 and permitting them to be pulled apart and thrown clear of the fuze nose I by the spring leaf 7 as shown in Figure 2. Taking into account the speed reduction afforded by the gear train described above, it will be readily seen that the dial l8 may be calibrated to facilitate setting the dial for triggering action at any desired distance of air travel within wide limits.

Due to the characteristics of the load on the vanes in relation to the relativel large vane area, there is very little air slip on the vane, whose rotation is therefore essentially a function of air travel rather than air speed. Hence, the calibration and setting of the arming mechanism is substantially independent of the speed and is determined by the distance traveled. When my arming device is used on bombs which may be released from an airplane at various speeds, it can still be set for a predetermined distance of travel prior to functioning, which is another advantage of my construction.

When the device is fully mounted and ready for use, an armin wire is inserted as shown. at 48 in Figures 1 and 3. This wire locks both halves of the cover together and also blocks rotation of vanes 26 so as to preclude the possibility of accidental arming while the wire is in place. Wire 40 is withdrawn immediately before releasing the projectile. The use of such a safety wire is broadly old in military projectiles.

Upon release of the arming delay device from the nose of the fuze during flight, the fuze is then permitted to function in its usual way. It thus will be seen that the device of the present invention provides an effective means for delaying the arming of conventional fuzes for a predetermined time of flight Which may be varied over a wide range. It is advantageous that the device may be utilized without modifying the conventional fuzes and that, at the same timef the device will not interfere with the functioning of the fuze after the desired arming delay has been accomplished.

In view of the above description of a specific embodiment of the invention it' will be apparent that the same may be susceptible of variation by one skilled in the art within the scope of the invention, and all such modifications are intended to be included within the scope of the following claims.

I claim:

1. An arming delay device for a projectile fuze having an arming vane comprising two hingedly connected cover members constructed and arranged to be closed about and engage the nose of the fuze to shield the arming vane from the air stream, a spring member connected to said members to move them to an open position and to disengage them from the nose of the fuze, means for locking the cover members in closed position on the nose of the fuze, and actuating means controlled by the flow of air during flight of the projectile for moving the last named means to an unlocked position during a pre-- determined distance of air travel said actuating means comprising'an air vane, a reduction gearing actuated by said air vane, and means actuated by said gearing after a predetermined rotation thereof to unlock said cover.

2. An arming delay device for a projectile fuze having an arming vane comprising a plurality of hingedly connected cover members constructed and arranged to be closed about and engage the nose of the fuze to shield the arming vane from the air stream, a spring member connected to said cover members to move them to an open position and to disengage them from the nose of the fuze, a member rotatably mounted on one of the cover members and having a slot therein, an extension on the other member constructed and arranged to be received through the slot in the rotatably mounted member and to maintain the cover members in closed position when the slot is rotated out of alignment with the extension, and. an air vane connected to said rotatable member for aligning the slot with the extension during flight of the projectile.

3. A mechanism for locking an arming delay device on the nose of a fuze for a predestined distance of air travel comprising a member rotatably mounted on the device having a slot therein, a member pivotally mounted on the device for engaging and disengaging the device on the fuze, a spring member on said device urging said pivotally mounted member away from the rotatably mounted member to disengage the device from the fuze, an extension on the pivotally mounted member constructed and arranged to be received through the slot in the rotatably mounted member and to be retain-ed by the member when the slot is rotated out of alignment with the extension, an air vane, and a gear train for connecting the air vane to the rotatably mounted member to rotate the slot into alignment with the extension during air travel.

4. A mechanism for locking an arming delay device on the nose of a fuze for a predestined distance of air travel comprising a member rotatably mounted on the device having a slot therein, a member pivotally mounted on the device for engaging and disengaging the device on the fuze, a spring member on said device urging said pivotally mounted member away from the rotatably mounted member to disengage the device from the fuze, an extension on the pivotally mounted member constructed and arranged to be received through the slot in the rotatably mounted member and to be retained by the member when the slot is rotated out of alignment with the extension, an air vane, and a gear train for connecting the air vane to the rotatably mounted member to rotate the slot into alignment with the extension during air travel, and clutch means for disconnecting the rotatably mounted means from the gear train to facilitate manual rotation of the rotatably mounted means.

5. An arming delay device for a fuze having an arming vane comprising means releasably attachable to said fuze for preventing rotation of said arming vane, said last means including releasable latch means for retaining said rotationpreventing means in place, a lightly loaded air vane mounted on said device for rotation during free flight of an attached fuze, a reduction gear train operated by rotation of said lightly loaded air vane, and means for operating said latch means after a predetermined number of turns of rotation of said lightly loaded air vane to release said releasabl attachable means from said f-uze to enable rotation of said arming vane.

6. An arming delay device for a projectile fuze having an arming vane comprising a plurality of connected cover members arranged to be closed about the nose of the said fuze to shield said arming vane from the air stream, means for disengaging said cover members from the said fuze, locking means for preventing the operation of said disengaging means, and actuating 6 means to move said locking means to an unlocked position upon a predetermined distance of free air travel, said actuating means comprising an air vane, a reduction gearing actuated by said air vanes, and means actuated by said gearing after a predetermined rotation thereof to unlock said cover members.

JACOB RABINOW.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 676,139 Klumak June 11 1901 1,643,385 Lafitte Sept. 27, 1927 1,788,856 Bossone Jan. 13, 1931 2,101,082 Mathsen Dec. 7, 1937 2,396,245 Butler Mar. 12, 1946 FOREIGN PATENTS Number Country Date 113,189 Switzerland Jan. 2, 1926 

